Method for obtaining images on metals

ABSTRACT

A METHOD FOR OBTAINING IMAGES ON METAL SURFACES, WHEREIN THE REPRODUCTION IS MADE ON THE METAL SURFACE FOR THE IMAGE TO BE OBTAINED BY SILK-SCREEN PRINTING USING A PROCTECTIVE INK CAPABLE OF WITHSTANDING A MECHANICAL SURFACE ABRASION ACTION AND ACID RESISTANT; THEN MODIFYING THE CONDITION FOR THE REMAINING PORTION OF THE SURFACE AND FINALLY REMOVING THE PROTECTIVE INK SO THAT THE PATTERN WILL APPEAR BY CONTRAST BETWEEN THE PROCESSED AND UNPROCESSED SURFACES.

se tyls', 1973 3,759,753

METHOD FOR OBTAINING IMAGES 0N METALS G. BECCA ETAL Filed June 22, 1971 F/OT/ INVENTORS GlUSEPPE BECC ROBERTO ORIG A GI ATTORNEYS United States Patent 3,759,753 METHOD FOR OBTAINING IMAGES ON METALS Giuseppe Becca, Via Savona 94, and Roberto Origgi, Via Rubens 23, both of Milan, Italy Filed June 22, 1971, Ser. No. 155,520 Claims priority, applicatigp7gtaly, July 20, 1970, Int. Cl. C23f 7/02 U.S. c1. 148--6.3 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a method for obtaining images ongenerally metal surfaces, and particularly on steel articles or panels by a panel glazing operation and an oxidation colouring process. The invention also relates to the metal articles or panels having the images as provided by the claimed method.

This invention is proposed for providing novel decorative means to obtain on generally metal surfaces, and particularly steel panels, any images by taking advantage of the chemical and/or physicalproperties of the metals, allowing also the exploitation of the invention on an industrial scale, in addition to solving aesthetical problems by novel means. According to the claimed method, the metal surface, in the case subjected to oxidation precolouring by heat treatment when steel or iron material panels are concerned with, is given the reproduction by a silk-screen printing process for the desired image or images using a per se known protective ink capable of withstanding a mechanical abrasive actionfand-"acid resistant; the metal surface is mechanically and/or chemically processed so that its surface aspect will be altered, then removing the protective ink to cause the desired image or images to appear by contrast between the processed and unprocessed surfaces.

The invention will now be described herein in further details referring to a specific exemplary embodiment and appended drawings, in which FIGS. 1 to show the sequence as followed for the several steps in the method for obtaining an image on a steel plate which has been coloured by oxidation through a heat treatment and then subjected to a mechanical glazing process to provide the panel with the desired aesthetical effect. It is to be understood that the subject as shown in the appended drawings and discussed about hereinafter referring thereto is given by mere way of example and that further changes to the method will be specified as the description progresses.

Referring to the drawings and particularly to FIG. 1, it'will be seen that a general steel panel is shown therein, designated as a whole at 10 and obtained, for example, from a fiat steel plate or from roll steel cut and in the case preshaped to the desired flat or box-like form.

Initially, panel 10 has a quite smooth surface, as shown in the top half of FIG. 1, free of any oxidation or scratch trace. To this purpose and prior to any mechanical bending and shaping operations the panel may be subjected to, the panel surface can be suitably protected by a selfadhering plastic sheet (not shown) to retain the panel surface at a completely unaltered condition.

Then, after removing the above mentioned protection, if any, this steel panel is subjected to a heat colouring process, so that the steel plates will oxidize with varying colourings, the strength of which being proportional both to the temperature attained. by the panel and the nature of the panel.

Particularly, the method for colouring the steel panel by oxidation consists of evenly or unevenly heating the panel in induction furnaces or the like, or manually by torches, to that temperature to which a desired tempering colour will correspond and then allowing it to cool. Thus, the colour corresponding to the attained temperature will indelibly remain on the surface, as schematically shown on the bottom half of FIG. 1.

Of course, the possibility of selecting the range of colours is restricted to that of the surface oxides which can build up on the steel panel.

By way of not limiting example, we specify that for stainless steels of the austenitic type 18/8 and normally steel A151 304, the indicative temperatures and corresponding oxidation colourings are listed in the following table:

The finishing of the metal panel surface may be whatever, such as semiglossy, opaque, bright, mirror-like as well as the nature of metals, particularly steel, may be whatever depending on the environment the panel is to be exposed to; for example, in particularly corrosive environments, such as in proximity to the sea and contaminating sources, it is possible and convenient to use special stainless steels, such as AISI 316 and A181 304 steels.

After the panel with the desired colouring has been prearranged at the desired position and with the desired poychrome effect, then attention is paid to the image so be obtained and which, as suitably processed, is transferred on a silk-screen frame.

As to this step, the universally well known normal conventional methods are followed to obtain a printing silk-screen picture.

Then, by using a special ink, commonly known and marketed by the Argon Service Co., a U.S. firm, under the denomination of Scraping Resist, this ink being thoroughly solvable in trichloroethylene or acetone, not clogging the fabric meshes of the silk-screen frame, is acid and mechanical abrasive action resistant, the silkscreen printing is carried out for the image 11 on the oxidized panel, as schematically shown in FIG. 2.

After printing the desired image or images at the preselected position on the panel, all the panel portion unprotected from said ink is deoxidized, by using a solution of H 0 and HCl in the higher proportions the faster would be the oxide removal and consistently with the non-toxicity degree of the solution; good results have been achieved with a 50% H 0 and 50% [HCl solution.

Once the panel surface has been rinsed and cleaned, a white steel surface will be now provided, this surface having one or more image zones, one of which is shown in FIG. 3 at 11, covered and protected with said special silk-screening ink.

The following processing on the steel panel is optional, and is carried out by following the subtractive method, or better to say by material removal through a smooth abrasion throughout the entire unprotected plate surface. This smooth abrasion or glazing is effected according to a preset direction and is carried out by using a glazing machine carrying special silicon carbide or aluminium oxide rollers which, by variable speed and such a glazing will modify the original finishing of the panel surface, at the portion obviously exposed from the protective ink (FIG. 4); said special rollers are commercially known as Scotch-Brite and are available and marketed by 3M-Minnesota, substantially comprising rollers having a partially resilient cellular structure, incorporating abrasive granules so that the abrasion action on the metal panel surface will not be deep and suitably endured by the protective ink layer at the image zones.

After the optional glazing operation on the metal panel surface, the protective ink is removed from the image zones by using a suitable cloth soaked in trichloroethylene or acetone to complete cleaning and clear appearance of the image or images, which will appear clear and rich in tones on a glazed surface background, as shown in FIG. 5.

Obviously Where the glazing operation should be omitted, the image or images would be provided by the oxidation colouring only.

Of course, the method just described could be carried out according to other many changes; for example, a plurality of silk-screening or countersilk-screening operations could be effected in different directions on the oxidized panel, or otherwise the oxidation could even be omitted and silk-screening be used alone to fix and form the image on the panel. Obviously, in the latter case, not coloured images are obtained on a white background, or the contrast between the image and panel background surface is achieved only by modifying the original finishing of the panel surface. Moreover, in this case, the panel may be of any metal.

Thus, it will be understood that according to the invention there is a very wide range of possibilities in reproducing images on metal, wherein not only existing images and subjects can be reproduced, such as photographs, but also images and subjects can be created as arising from a creative process of pure imagination.

The images so obtained have a very wide range of effects, it being possible to use the reflection, brightness or opacity of the metal surface separately of in combination with the numberless changes in oxidation colour making an extremely wide application field for the invention. Thus, it is possible to design and make panels and articles for building industry, ironwork, as well as panels for insertion in fixtures, furniture and wherever the metal is used, giving rise to a novel decoration.

Of course, what has been stated and described referring to the appended drawings has been given by mere 4 1* way of example and further utilization fields can be found without departing for this from the covering field of the invention.

What is claimed is: 1. A method of applying a predetermined pattern of complex contrasting areas to a metal surface comprising the steps of 1 heating the metal surface to impart a nonuniform coloring thereto,

silk screening a protective coating to selected areas of the metal surface corresponding to the complex contrasting areas of the pattern,

treating the exposed metal surface to impart a modified finish to unprotected surface areas thereof, and removing said protective coating to expose the underlying nonuniformly colored surface areas thereby defining the predetermined pattern.

2. The method as recited in claim 1 wherein said treating step comprises abrading the unprotected surface areas.

3. The method as recited in claim 1 wherein said heating step comprises imparting a colored finish to the metal surface by heating at least a portion thereof to a preselected temperature.

4. The method as recited in claim 3 wherein said treating step comprises removing the colored finish from the unprotected surface areas by exposing the same to an inorganic mineral acid solution.

5. The method as recited in claim 3 wherein said treating step comprises abrading the unprotected surface areas.

6. A metal object having a surface finish pattern ap plied by the method of claim 1.

References Cited UNITED STATES PATENTS 2,243,787 5/ 1941 Batcheler 1486.24 3,035,990 5/1962 Davis et al 15611 1,977,270 10/ 1934 Field 148-6.35

378,442 2/ 1888 Hafely 1178 X 1,655,483 1/ 1928 Wheeler 148--6 1,845,016 2/1932 DAtri 51-312 X 2,355,007 8/1944 Mitchell 1486.14 R X 2,059,053 10/1936 Stareck 148-6.35'X

RALPH S. KENDALL, Primary Examiner US. Cl. X.R. 

